U.S. patent number 3,805,104 [Application Number 05/275,565] was granted by the patent office on 1974-04-16 for low inertia rotor for dynamo electric machines, and method of making the same.
This patent grant is currently assigned to Etablissements E. Rajonot. Invention is credited to Gerard Lacroux, Pierre Margrain.
United States Patent |
3,805,104 |
Margrain , et al. |
April 16, 1974 |
LOW INERTIA ROTOR FOR DYNAMO ELECTRIC MACHINES, AND METHOD OF
MAKING THE SAME
Abstract
A hollow insulating cylinder with conductors thereon is placed
over an internal metallic tubular support which is supported by an
end disk at one end, and open at the other, the open end being
flared for stiffness.
Inventors: |
Margrain; Pierre (Malakoff,
FR), Lacroux; Gerard (Malakoff, FR) |
Assignee: |
Etablissements E. Rajonot
(Malakoff, FR)
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Family
ID: |
27249168 |
Appl.
No.: |
05/275,565 |
Filed: |
July 27, 1972 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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52595 |
Jul 6, 1970 |
3694907 |
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Foreign Application Priority Data
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Jul 10, 1969 [FR] |
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69.23496 |
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Current U.S.
Class: |
310/266;
310/207 |
Current CPC
Class: |
H02K
3/26 (20130101) |
Current International
Class: |
H02K
3/04 (20060101); H02K 3/26 (20060101); H02k
001/22 () |
Field of
Search: |
;310/266,261,202-207,264,67,42,43,171,45,265,49A,DIG.6 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Skudy; R.
Attorney, Agent or Firm: Flynn & Frishauf
Parent Case Text
The present application is a division of Ser. No. 52,595, filed
July 6, 1970, now patent 3,694,907.
Claims
1. Low inertia rotor structure for dynamo electric machines having
discrete conductors forming at least one winding loop thereon
comprising
a thin, hollow support cylinder made of metal (11, 19), said metal
support cylinder being open at one end and having an outwardly
flaring end section (25) at said open end;
a metal end support disk (20), secured to and supporting the thin
metal cylinder at the other end thereof and providing a connection
to a shaft (21);
a layer of insulating material (19') in cylindrical form
surrounding the outside of said metal cylinder (11, 19); and an
array of adjacently located conductive strips forming an entire
winding loop on said
2. Rotor according to claim 1 comprising a support sheet of
insulating material rolled in cylindrical form and carrying said
conductive strips secured thereto, said array comprising
axially extending conductor sections interconnected by integral
conductive sections extending essentially circumferentially and
folded about said insulating support sheet, said insulating support
sheet separating the axially extending conductor sections of any
one conductor applied to the sheet from the other, superposed
axially extending conductor sections of
3. Rotor according to claim 2, wherein the conductor sections are
applied as unitary conductive bands to one side of an insulating
support sheet, said sheet having a fold line (X--X) thereon;
and the sheet of insulating material is folded hinge-like around
said fold line against itself with the side free from conductors at
the inside of
4. Rotor according to claim 1 wherein the insulating material
comprises an insulating support sheet which is soft and has a
thickness in the order of tens of microns, rolled in cylindrical
form, and placed on the metal
5. Rotor according to claim 4, wherein the insulating support sheet
is a
6. Rotor according to claim 2, wherein the conductive strips are
metal bands;
removable sections (KLM) are provided between said strips, said
strips being folded toward each other in the region of said
circumferential sections; said support sheet being a hollow
cylinder of insulating material, and said removable severing
sections are removed prior to
7. Rotor according to claim 1 wherein the insulating material
comprises a rolled, longitudinal sheet of insulating material with
said conductive strips secured thereto and located on the support
cylinder (11, 19) with the insulating material contacting the
outside of the metallic support
8. Rotor according to claim 1, wherein said thin hollow cylinder is
of
9. Rotor according to claim 1 wherein said hollow metal support
cylinder
10. Rotor according to claim 2 comprising a plurality of winding
layers each including integral conductive strips; said conductive
strips being folded in zig-zag form;
and cylindrical sheets of insulating material (17) separating,
facing conductive strips forming portions of the winding loop to
insulate said
11. Rotor according to claim 2, wherein said sheet material having
said conductive strips thereon, when rolled into cylindrical form,
has an overlapping seam;
said sheet being shaped to conform to the outline of the first and
last conductor;
and the overlapping portion of the sheet forming the seam with
conductors thereon being adhered together with the conductor
section forming a continuous circumferential array, the first and
last conductors fitting uniformly against each other, with
insulating sheet material therebetween, and without break in the
continuous uniformity of spacing of the axially
12. Rotor according to claim 1, wherein the hollow metal support
cylinder is of about 0.25 to 0.3 mm thick nickel.
Description
The present invention relates to rotors for dynamo electric
machines, and more particularly to low-inertia rotors utilizing
printed, or laminated circuit techniques in their manufacture.
Servo and control motors, particularly motors used in data
processing equipment require rotating elements which have as low an
inertia as possible, so that they can rapidly reach a stable
commanded speed from rest, or from any other speed. Such motors are
also needed to control tapes, particularly for tape transport in
computer equipment which have high start-stop requirements with
extremely low inertia.
Various types of motors with low inertia have been developed. A
particularly useful type employs a rotor formed as a hollow
cylinder which rotates within an air gap of a magnetic circuit
which is fixed. The winding of the rotor is formed of coils having
a single loop formed as printed or laminated circuits. Laminated
circuits should be understood to mean circuits in which conductive
strips are applied to an insulating support base, for example, by
adhesives, crimping or other methods known in the art.
Rotors of the type forming a hollow cylinder are usually made by
first preparing an outline, that is a printed (or laminated)
drawing of the windings as a printed circuit and carrying the
conductors for current flowing in one direction and then the return
conductors. The two outline drawings, first flat, are then placed
over another, rolled in cylindrical form, and then interconnected
at their terminal ends in order to form the loops of the windings.
This method of assembling requires two interconnections; one at the
rear face, where the forward and the return current carrying
windings are interconnected and the other on the forward end, which
may also be called the "collector end." Difficulties have been
experienced in making the connections, particularly in making the
connections at the back end where the windings are to be
interconnected, which difficulties have been solved only by
manually interconnecting one conductor after the other in the
region of their junctions.
It is an object of the present invention to provide a rotor of low
inertia, in which the windings are formed by printed or laminated
circuits techniques.
SUBJECT MATTER OF THE PRESENT INVENTION
Briefly, a hollow metal support cylinder of a metal having a high
conductivity, such as nickel is used, the cylinder being thin
(about 0.25 to 0.3 mm thick) on which an insulating material is
applied, and electrical conductors are placed on the insulating
material, the electrical conductors being in printed or laminated
circuit form. In a preferred form, the conductors are applied to a
thin soft support foil, such as "Mylar" having a thickness in the
order of tens of microns, which is rolled over the metal support
cylinder.
A hollow support cylinder may be made by electrolytic deposition
about a mandrel which is later removed. The mandrel itself may
consist of a central core of tough material surrounded by a
metallic covering material having a low melting point which is
readily melted out.
IN THE ACCOMPANYING DRAWINGS
FIG. 1 illustrates a plan developed view of a complete loop of a
winding for the rotor of a dynamo electric machine;
FIG. 2 is a developed plan view of the outline shape of a printed
or laminated surface, with some conductors thereon, forming one
embodiment of a starting point in making the rotor in accordance
with the present invention;
FIG. 3 illustrates an almost completed rotor in perspective
view;
FIG. 4 is a longitudinal, partly broken away and crosssectional
view of a rotor assembled in a machine, shown in schematic
form;
FIG. 5 is a top plan view of the lay-out of the windings in
accordance with a different embodiment;
FIG. 6 is a partial schematic cross-sectional view, in longitudinal
section, of the hollow metal cylinder being applied to a mandrel
which has not yet been removed;
FIG. 7 is a schematic longitudinal view through a pressure chamber
illustrating a step in the process of manufacturing a complete
rotor;
FIG. 8 is a partial longitudinal cross-sectional view, in section,
of an assembly of a support cylinder and winding after the process
of FIG. 7 has terminated;
FIG. 9 is a schematic longitudinal half cross-sectional view of a
core and mandrel in accordance wth another embodiment of the
present invention;
FIG. 10 is a partial cross-sectional longitudinal view to a greatly
enlarged scale of a rotor of FIG. 4, which is banded with a metal
band;
FIG. 11 is a lay-out drawing for a multilayer winding;
FIG. 12 is a partial longitudinal cross-sectional view of one
multilayer winding, after folding of the circuit of FIG. 11;
and
FIG. 13 is a partial transverse cross-sectional view of the coil of
FIG. 12 showing how the conductor layers, among each other are
interconnected.
The type of rotor to which the present invention relates is best
seen in FIG. 4. The hollow cylinder 11 has coil windings 12 mounted
thereon. An air gap is formed between two magnets generally,
schematically indicated as N and S and a central core 13. A bearing
such as balls 14 within a bearing race, not shown, provides for
rotation of the rotor assembly 10 consisting of the cylinder 11 and
windings 12, with respect to core 13. A pair of brushes 15 run on a
commutator, the elements of which may be formed by straight
terminal portions of the conductor forming the winding.
The armature 12 is of the type generally known as "interlaced" and
is formed of individual winding units, each one of one or more
layers. since the winding arrangement itself is well known, it will
not be described again in detail but a brief review will be given
of the winding lay-out to define the type of armature described in
detail.
FIG. 1 illustrates a coil formed of a single winding. In this
winding, a "going" conductor A (shown in full lines) is connected
to a straight input portion E. It is connected by means of a rear
bridge to a "return" conductor R shown in broken lines, having a
straight output terminal portion S. For purposes of further
description, the input and output portions E, S will be termed "the
foward" portion and the interconnecting bridge "the rearward"
portion of the winding.
A number of identical coils are arranged, all around the rotor
overlapping one above the other in such a manner that the forward,
or "going" conductors all are located next to each other in the
longitudinal sense of the rotor, however, in two layers, only one
of which is formed by the going conductors A. The second layer is
formed by the return conductors R. The input connection of each
coil which is on one of the layers is connected to the output of an
adjacent coil of the other layer, thus, giving a complete endless
winding closed in itself, and generally termed an interlace wound
armature. This type of armature is selected as an example, although
the invention is applicable to any kind of armatures, particularly
to those in which the conductors have two layers.
In accordance with the present invention, the outline of the
armature 12 is first provided on a flat sheet of printed circuit
such as shown in FIG. 2. The carrier for the printed circuit is a
thin, flexible sheet material having a conductive surface applied
to one side, for example, copper. The copper may be in sheet form
printed, or laminated thereto. It is engraved in accordance with
the image of the entire winding to be applied, that is the terminal
end portions E, the going conductor A, the connecting bridge at the
back of the armature, the return conductor R and the final terminal
portion S. A group of forward conductors Al. . . A.sub.n as well as
the return conductors Rl. . . R.sub.n of armature 12, when
developed and in plan view, will appear as shown in FIG. 2. Taking
the axis X--X of this representation as a hinge point, and doubling
over the broken line portion, one obtains a flat sheet of two
superimposed layers, which form the conductors. It is readily seen
that the array of conductors forms a family of zig-zag, parallel
tracks, the array of one side of the hinge X-X having the same
longitudinal dimension as the other portion, but at opposite sense
of curvature, with respect to the left-right direction of FIG. 2.
Each one of these tracks will then represent a going conductor and
a return conductor, respectively, of the armature and thus, form
one winding of armature 12.
In order to form a cylindrical armature, by means of the circuit
assembly of FIG. 2, end portions of the insulating support 1 are
cut to match the outlines of the first and last of the conductors
Al-Rl and An-R.sub.n. Thereafter, the flat sheet is folded along
hinge X--X so that the insulating sheet will be at the interior of
the fold. The insulating sheets can then be adhered together, and
the flat, folded form is rolled by hand or over a cylindrical
mandrel into form of a cylinder in which the first conductors Al-Rl
will be along side with the respective last conductors An-Rn. FIG.
3 illustrates, that due to the curvature in the cylinder, several
of the "going" conductors A will define the projecting portion 2,
wherein those of the return legs Rl . . . will define a hollow or
indented portion 3, inverse to the projecting region 2. The last
going conductors An . . . as well as the return conductors Rn . . .
will be, with respect to the first ones, reversely indented or
projecting. When the first and the last conductors are juxtaposed,
the projections 2 will match exactly within the indentations 3 and
can be placed above the other. Since the insulating face of the
carrier having the original design is folded interiorly, the
projection 2 will be placed insulation, against insulation and,
upon adhering together the entire assembly into a closed cylinder,
the circuit of FIG. 2 is transformed into hollow cylinder having
practically no trace at the junction. The exterior face of the
cylinder will support one of the layers of conductors, for example,
the going conductors, whereas the interior face will support the
other layer of conductors, that is the return conductors. The two
layers are thus, naturally insulated from the other. There is no
interruption between going and return conductors of any one
winding. Nevertheless, the winding terminals are free at the
collector side. An input terminal of each winding is opposite the
output terminal of an adjacent winding, in a suitable position for
their interconnection. A simple way to interconnect the terminal
strips electrically consist in forming a small opening 4 in the
printed or lamina circuit, and then filling these holes with a
small plug of connecting metal, such as tin which can be obtained
by dipping the terminal ends in a solder bath, or placing a small
grain of copper through the holes providing for adhesion, for
example, by compression, heating or other suitable methods. The
holes 4 may be pierced in the circuit in flat form, at the same
time when the circuit outline is engraved or otherwise
manufactured. In general it is not necessary to provide a special
connecting element of the windings of armature assembly 12 to a
separate collector, since the straight conductive portions which
form the input and output terminals E, S, respectively, may
directly serve as the tongues of the collector (see FIG. 4).
Armature 12 as described, utilizes a support for the printed
circuit which is thin and plyable and which can be readily bent, as
well as being rolled in cylindrical form. It may, for example, be a
sheet of polyester, Mylar or the like of several tens of microns in
thickness. The copper sheet on the support may have any desired
thickness, depending on the current carrying capacity required of
the armature 12 and by the width of the air gap in which the
armature 12 is to operate. In order to utilize the terminal ends of
the windings as the collector tongues, the thickness of the
terminal ends can be increased by electrolysis at the point where
the brushes will track, particularly when the thickness of the
copper conductors forming the winding is very small, such as
several microns only.
Embodiment of FIG. 5: The outline of the armature 12 is cut flat
from a single sheet of metal, such as copper. Conductors Al. . and
Rl . . have the same general form as that shown in FIG. 2; they are
interconnected together by small metal tabs, KLM located
conveniently and preferably at the terminal end regions E, S,
respectively, as well as at the level of the hinge X--X. The
interconnection of the conductors among each other prevents
deformation and spreading apart; interconnection at three points
permits ready handling of the cut sheet of copper. In order to form
the armature by means of a copper sheet, it is folded in half along
the hinge X--X, and bent round over a cylindrical mandrel, or
directly over a hollow cylinder 11. After being shaped, a thin
insulating tube is placed in the interior of the fold, that is
between the layers of going conductors A and the return conductor
R. Thereafter, input and output conductors are interconnected, and
then the small tabs K, L, M are cut to sever the conductors both at
the collector end, as well as at the rear end of the armature.
In accordance with a variation, the sheet of copper is cut and
adhered to an insulating, flexible sheet before being bent, and
then bent along hinge axis X--X and shaped as before.
Embodiment of FIGS. 11 and 12: To make a multi-layer armature 12,
flat winding outline in accordance with FIG. 11 is prepared again
as a printed circuit similar to the embodiment of FIG. 2, with
interconnected groups of conductors as described in connection with
FIG. 5. A plurality of going and return conductors will be
provided; as seen in FIG. 11, the going conductors A.sub.la
-A.sub.na are connected to return conductors R.sub.la . . .
R.sub.na to going conductors of the second layer A.sub.lb . . .
A.sub.nb and in turn to the return conductors of the second layer
R.sub.lb . . . R.sub.na. As first fold, the conductors are then
hinged about axes X--X and Z--Z to form the going and return
conductors of the two layers with supporting insulating material 16
therebetween, similar to the insulating material 1 of FIG. 2, or,
if the conductors are made of interconnected strips of copper, for
example, a sheet insulating material can be interposed to separate
the going and return conductors. Thereafter, a bend in the opposite
direction is formed above hinge axis Y-Y with an insulating sheet
17 (FIG. 12) therebetween. The array of conductors forms as group
of tracks in zig-zag parallel arrangement. Each one of the
conductive tracks represents going and return conductors of a coil
having two windings. Only the going conductors of the first
winding, A.sub.la...A.sub.na and the return conductors of the last
winding R.sub.lb...R.sub.nb have terminal ends which are straight
in order to form the input and output portions E, S of the coils.
Input E may, directly, form also the commutator segments.
The embodiment of FIG. 11 is similar to that of FIG. 2, except that
it has two windings. Similarly, insulating support film 16 is cut
in accordance with the outline of the terminal conductors A.sub.la
- R.sub.la - A.sub.lb - R.sub.lb l and A.sub.na - R.sub.na -
A.sub.nb - R.sub.nb The outline pattern, just cut, may then be
folded along hinge Y--Y with the conductors facing each other (that
is the insulating sheet at the outside), and the insulating sheet
17 is interposed and the layers of windings are then adhered
together (see FIG. 12). The pattern is folded back upon itself upon
axes X--X and Z--Z. The going conductors of the second layer
A.sub.lb . . . A.sub.nb and the return conductors of the first
layer R.sub.la. . . R.sub.na are thus separated by the insulating
sheet 17. After adhesion together of all insulating sheets, various
layers of the conductors will be superposed as illustrated in FIG.
12. The entire assembly folded and adhered together is then rolled
in the form of a cylinder, ends are covered as best seen in FIG. 13
and fixed by adhesives.
Armatures having a larger number of winding layers than two may be
made in similar fashion. The embodiment described in connection
with FIGS. 11 and 12, shows the winding layers folded along fold
hinge lines, with insulating sheets interposed between adjacent
layers of conductors. Insulating sheets may be either the support
for the conductors themselves or may be separate sheets similar to
sheet 17, inserted flat and in tubular form after the winding
arrangement has been rolled into a cylinder.
The armature sub-assembly 12 in accordance with the invention is
mounted on a hollow cylinder 11 (FIG. 4) to form the low inertia
rotor assembly 10.
The hollow cylinder 11, in accordance with the invention, must be
very light so that its inertia does not substantially increase that
of the armature assembly. It must be sufficiently thin to take up
little space in the air gap and, additionally, must be sufficiently
rigid to retain a circular shape. Cylinder 11 is of metal and the
exterior surface thereof is protected by an insulator. In case good
heat removal from the armature is desired, cylinder 11 may also be
made of beryllium oxide, a ceramic having a heat conductivity which
is almost equal to that of copper. The metal cylinder should,
preferably, have one or several of the following characteristics:
It should be capable of being applied by electro deposition in a
thin layer having low internal tension, that is less than 100kg.
per square cm. For example; it should have good mechanical
strength, that is, be very rigid, resistant to compressive forces,
and have a high young modulus, while having a low volumetric mass;
and it should have a high electrical resistivity so that the rotor,
in operation, will have little eddy current losses.
A suitable metal is nickel. A hollow metallic cylinder 11, made of
nickel, can be made in accordance with the present invention and as
claimed in parent application Ser. 052,595 now U.S. Pat. No.
3,694,907, as follows (with reference to FIG. 6); a layer 19 is
electro-deposited in a nickel sulfamate bath or a similar bath.
Layer 19 will have a homogeneous thickness in the order of from
0.25 to 0.30 mm. applied on a tough cylindrical core 18, such as
soft iron. Core 18 has a cylindrical body 20 and a coaxial
cylindrical extension 21 which functions as mechanical axis first
for the entire core 18 during the manufacture of the hollow
cylinder 11, and then may function as a shaft for the hollow
cylinder 11.
Core 18, with its exterior layer 19 of nickel is carefully machined
for roundness. Nickel layer 19 on core 18 is covered with adhesives
and insulating resin 19' and then the armature 12, previously
folded, is rolled thereon. The super-imposed layers of the armature
are adhered together. The armature itself may be formed as
previously discussed in connection with FIGS. 2, 5, or 11. After
adhering the end portion of the winding array of armature 12, the
entire sub-assembly of core-nickel coating -- winding is located in
a pressure chamber 22 (FIG. 7) in which an internally hollow
pressure bladder 23 is inserted. Pressure bladder 23 is inflated
through a duct 24 to apply itself snuggly against the outside of
the sub-assembly armature 12 -- layer 19 -- core 18, to remain
there for at least a part of the period of time of polymerization
of the adhesive resin, or during another adhesion process. Heat may
be supplied if desired.
The sub-assembly: Core 18 -- layer 19 (with applied insulation
19')--armature 12 is then removed from the pressure chamber 22 and
machined to remove almost, or all of the cylindrical material 20 of
core 18 (FIG. 8) leaving, however, the nickel layer 19 in tact.
This may be accomplished by means of mechanical machining, finished
by chemical attack. Nickel layer 19 and the remaining portions of
core 18 (FIG. 8) will then form the hollow cylinder 11 illustrated
in FIG. 4 and referred to in the preceding description.
For improved rigidity, the nickel layer 19 may be formed with a
bulged up cylindrical edge 25 (FIGS. 6 and 8). The core 18 itself
may already be formed with an enlarged end portion 26 (FIG. 6) to
effect deposition in the shape shown to an enlarged scale in FIG.
10.
In accordance with the present invention, the core in which the
hollow cylinder will be obtained may be similar to core 27 (FIG. 9)
which is partially composed of tough metal and partially a metal
having a low melting point, in order to facilitate removal of the
cylindrical body which is not necessary, after the layer 19 of
nickel, or another metal of suitable characteristics, has been
applied on the core. Core 27 has a central shaft 28 and disc-like
end portion 29, also of tough metal, as well as a cylindrical body
of low-melting point metal, or alloy; a melting temperature of from
100.degree. to 130.degree. C. in suitable.
After the roundness of the core 27 is accurately established, it is
first covered with a thin layer of copper, for example, by
electrodeposition, and then covered by a layer 19 of another metal
such as nickel. Nickel layer 19 has the armature 12 applied thereto
as described previously. The sub-assembly: Nickel-covered core 27,
and insulation 19'; and armature 12 is then if desired, inserted in
the pressure chamber (FIG. 7); to remove the metal, it is subjected
to a temperature just above the melting point of the metal, or the
metal alloy forming the cylindrical body 30. The metal forming body
30 is carved out, leaving intact the layer 19 of nickel with an
internal thin film of copper. Any residual low-melting point metal
is removed by machining. The copper base film forming the plating
substrate may either remain, or may be removed chemically.
Rotors 10 which are to operate at high speed preferably are banded
on the outside. In accordance with the invention, and exterior
insulating layer 31 covers the conductor of armature 12, which for
mechanical strength may be metalized in accordance with
electrodeposition techniques, for example, by a thin layer 32 of a
metal such as nickel (see FIG. 10). In order to make the rotor as
light a possible, relief holes 33 (FIG. 8 and FIG. 9) may be
pierced through the end faces.
As had been seen, the motor is easily manufactured from a flat,
plain sheet. The lay-out of the conductive strips to form the
windings may be carried out by well known printed circuits or
laminated circuit techniques on a flat surface, which are then
folded as desired. Contrary to the prior art, which requires
separate manufacture of going and return conductors, and
interconnection of the windings both at the commutator end as well
as at the rear end of the armature, the present invention provides
a rotor structure and a method of making such a rotor in which the
number of parts to be handled and to be made is decreased, thus,
substantially facilitating alignment and interconnection of the
separate parts. The only interconnection to be made is the
collector side. In accordance with the invention, the two terminal
conductors of the armature assembly, when rolled in a cylinder,
match exactly without necessity of providing interconnection of the
conductors of the windings, one each, thus omitting additional
connection points and simplifying manufacture and assembly.
The winding 12 can be applied directly over the hollow cylinder 11,
if this hollow cylinder 11 is covered with a thin layer of
electrically insulating material before the winding 12 is applied
thereover. After applying an insulating layer over the hollow
cylinder 11, a thin and uniform metal coating is applied over the
insulator on which a conductor of the winding 12 are then formed in
accordance with known processes. If the winding 12 is to contain a
plurality of superimposed layers, the portions described above may
be repeated several times, that is, after forming the conductors of
winding 12 a thin insulating layer is applied thereover, then a
metal coating on which the second winding layer is formed, and so
on. Since the formation of this winding is carried out in
accordance with known processes, they are not described or shown in
detail. The windings so obtained may be secured by a binding or
hoop, as described above.
The present invention has been described specifically in connection
with single and multi-layer windings armatures having interlaced
windings; other winding systems, and different winding arrangement
may be used within the scope of the inventive concept.
* * * * *